An 11th-hour White House push to give President Trump a major legislative victory in his first 100 days in office broke down late Thursday as House Republican leaders failed to round up enough votes for their bill to repeal the Affordable Care Act.

Some White House officials had hoped for a vote on Friday on a measure to prove that Trump was making good on his promise to undo the sweeping health law — President Barack Obama’s signature domestic achievement — in his first 100 days in office.

But seesawing commitments and the reservations from numerous lawmakers throughout Thursday laid bare the difficulty that Republican leaders faced in trying to push through a repeal bill. While revisions to their bill won over conservative hard-liners in the Freedom Caucus this week, those same changes threatened to drive away other members, even some who supported the first version.

A senior House aide said late Thursday that there would not be a vote on the health bill this week. At least 18 House Republicans oppose the latest version of the bill, the American Health Care Act, and leaders can lose no more than 22 to win passage if all members vote. …